The Random Phase Approximation (RPA) for total energies has previously been
shown to provide a qualitatively correct description of static correlation in
molecular systems, where density functional theory (DFT) with local functionals
are bound to fail. This immediately poses the question of whether the RPA is
also able to capture the correct physics of strongly correlated solids such as
Mott insulators. Due to strong electron localization, magnetic interactions in
such systems are dominated by superexchange, which in the simplest picture can
be regarded as the analogue of static correlation for molecules. In the present
work we investigate the performance of the RPA for evaluating both
superexchange and direct exchange interactions in the magnetic solids NiO, MnO,
Na3Cu2SbO6, Sr2CuO3, Sr2CuTeO6, and a monolayer of CrI3, which are chosen to
represent a broad variety of magnetic interactions. It is found that the RPA
can accurately correct the large errors introduced by Hartree-Fock -
independent of the input orbitals used for the perturbative expansion. However,
in most cases, accuracies similar to RPA can be obtained with DFT+U, which is
significantly simpler from a computational point of view.Comment: 9 page
